Re: [PATCH] ALSA: usb-audio: Skip probe-time interface setup for MSI MAG X570S ALC4080

[Takashi Iwai <tiwai@suse.de>]

On Mon, 26 Oct 2026 15:09:34 +0100,
Zak Brighton Knight wrote:
> 
> The Realtek ALC4080 USB audio on the MSI MAG X570S Tomahawk Max WiFi
> (USB ID 0db0:a073, the same ID as the MAG X570S Torpedo Max mixer map)
> has six streaming interfaces with 68 altsettings in total. For each of
> them, __snd_usb_parse_audio_interface() switches the interface to alt 0,
> initialises pitch and the sample rate and switches back, which costs
> about 64 ms per altsetting here, mostly spent inside usb_set_interface().
> Probing the card therefore takes about 6.4 seconds, on every boot.
> 
> That setup is redundant with snd_usb_endpoint_prepare() at stream-open
> time, so set QUIRK_FLAG_SKIP_IFACE_SETUP for this device.
> 
> Tested on 7.2.11 with the equivalent quirk_flags=0db0:a073:skip_iface_setup
> module option, re-probing the device via its sysfs "authorized"
> attribute: probe time went from 6.45 s to 0.57 s, all 68 altsettings
> are still listed in /proc/asound/cardX/stream*, and playback and
> capture work.
> 
> Assisted-by: LLM
> Signed-off-by: Zak Brighton Knight <zakbrightonknight@gmail.com>

Applied now.  Thanks.


Takashi